#include <stdio.h>
int main()
{
	int a,b,c,d,max;
	scanf("%d %d %d %d",&a,&b,&c,&d);
	max=a>b?a:b;
	max=max>c?max:c;
	max=max>d?max:d;
	printf("%d",max);
	return 0;
}